Introduction: Aphthous stomatitis is very common, affecting about 20-60% of the normal individuals to some degree. Although its etiology is not well-understood, it is multifactorial, and stress could be one possible triggering factor. Aims: The aim was to assess the prevalence of aphthous stomatitis and its association with psychological stress in both medical and dental graduate students. Materials and Methods: A cross-sectional study was conducted in 275 medical and dental student cohorts of an educational setup in India. Data were collected using a self-administered questionnaire, information regarding psychological stress, and 1-year period prevalence of aphthous stomatitis was collected. Data analysis was done with SPSS software version 20 (Chicago Inc., IL, USA). Categorical variables were compared using Chi-square test and comparison between mean stress scores and aphthous stomatitis was done with ANOVA and binary logistic regression was done. P ≤0.05 was considered as statistically significant. Results: The prevalence of aphthous stomatitis in the study population was 78.1% and males were more commonly affected than females. Among the student cohorts, final year MBBS and final year BDS students were highly affected than others, which is statistically significant. Conclusions: Stress increases the risk of aphthous stomatitis. Stress management strategies are necessary for medical and dental graduate students.

Aphthous stomatitis (also known as recurrent aphthous stomatitis [RAS], or a recurrent aphthous ulceration) is a common pathologic condition characterized by the repeated occurrence of benign and noncontagious oral ulcers, in otherwise healthy individuals. [1] These ulcers are very common, affecting about 20% of the normal individuals to some degree. [2] The onset is often during early adolescence, and the condition usually lasts for several years before it resolves. [3] These ulcers appear periodically and heal completely without scarring. In most of the cases, the ulcers last about 6-8 days, and ulceration episodes occur 3-6 times/year. [4] It does not show any gender predilection, and the peak age of onset between 12 and 19 years. First episode of aphthous stomatitis occurs before the age of 30-year in nearly 80% of the cases. [2]

Within the oral cavity, nonkeratinizing epithelial surfaces in the mouth are commonly affected, although the most severe forms, may also involve keratinizing epithelial surfaces (which are less common). [4] Symptoms range from a minor irritation to functional disability, that is, interfering with eating and drinking. The severe forms may be debilitating, even causing weight loss due to malnutrition. [5] The precipitating factors of RAS include stress, physical or chemical trauma, food sensitivity, hormonal imbalance, menstrual cycle, and genetic predisposition. Some investigators have noticed that low prevalence rate of RAS in smokers than in nonsmokers, increased incidence following smoking cessation, reduction of lesion upon resumption of cigarette smoking. [6] Stress has been emphasized as a major risk factor in RAS.

Until recent past, the proposed hypothesis was that stress may induce parafunctional habits such as tongue., lip or cheek biting, and thus causes trauma to oral soft tissues, and this trauma may predispose to ulceration. [7] A study reported by Pedersen revealed an insufficient evidence between levels of parafunctional habits and severity of RAS episodes and concluded that mental stress may act as a triggering or modifiable risk factor rather than etiological factor for aphthous stomatitis. [8] Most of the adults are not strangers to stress. Apart from affecting their mental state, stress effects are not completely understood, but involve a T cell-mediated immune response triggered by a variety of factors.

Medical professionals must endure an enormous amount of work related stress. [9] They are expected to be correct in all decisions and if they are wrong, a life could be lost. In addition, they have to be prepared to leave what they are doing at a moment's notice to attend to a medical emergency. [9] Mishra etal. reports that in a 2011 survey in the India, 58.2% of the doctors experienced high stress. [10] Besides that, 69% of surveyed doctors have suffered from some form of stress-related symptoms. Situation is similar in Jamaica, as reported by Hutchinson etal., where more than 50% of emergency physicians suffered from stress and its related impairment. [11]

Medical and dental students are also vulnerable to numerous stressors. They spend long hours studying for exams that will determine their future. Their curriculum is not simple, and the stress of trying to cope up with multitask can become overwhelming. In addition, student's first exposure to patients is very exciting and trying to live up to patient's expectation may be emotionally taxing. This exposure comes as early as in 3 rd year in their medical and dental curriculum in India. [12]

In the scientific literature, several factors have been linked to stress experienced as a response to students' efforts to meet academic performance requirements in dental school. The two most commonly reported factors were grade competition and heavy workload. [13] Both dental and medical students may also be stressed due to a perceived lack of competence in treating patients. [12],[13] Investigators reported that transition periods, such as graduating from preclinical to clinical training, were considered the most stressful times in professional education. [14] There is a dearth of knowledge in prevalence of aphthous ulcers and its relation to stress in medical and dental students. Hence, this study was conducted to assess the prevalence of aphthous stomatitis and its association with psychological stress in both medical and dental graduate students.

Materials and methods

Settings

A descriptive cross-sectional study was conducted at an educational setup, which consists of both medical and dental colleges in the same campus.

Participants

All the procedures followed in this study were in compliance with the Helsinki Declaration and the study protocol was approved by Institutional review board. Pilot study was conducted to assess the feasibility of the study, questionnaire validation and for sample size calculations. Based on the pilot study results, a total sample of 250 was sufficient to detect statistically significant difference of 10% with 95% confidence interval and considering design effect of two. Predicting 10% loss of data due to rejections, errors, etc., sample size has been adjusted to 275.

Participants were the students who are pursuing graduation in Medicine and Dentistry in above mentioned settings and subjects were selected through systematic random sampling (first subject was randomly picked by lottery method and then every 2 nd person was selected based on their roll numbers until sample size is achieved). Participants with systemic illnesses such as Behηet's Syndrome, Celiac or Crohn's disease and smokers were excluded.

Questionnaire

The self-administered questionnaire was used in this study which composed of 25 questions that include information about demographic data of the subject, the frequency, and intensity of stress symptoms and self-reported information about aphthous stomatitis. Psychological stress was assessed through the questions used in similar published studies. [14],[15] Reliability of the questionnaire was assessed with Cronbach's α, which was found to be satisfactory (0.84).

Data collection

All the selected participants were invited to a classroom, explained about the purpose of the study and questionnaires were distributed to the participants, who gave consent to participate in the study. Participants filled the questionnaires and any doubts in filling questionnaire were clarified by the investigators.

Statistical analysis

Data analysis was done with SPSS software version 20 (IBM, Chicago Inc., IL USA). Categorical variables like RAS versus course, gender, etc., were compared using Chi-square test. Comparison between mean stress scores versus gender was done with Student's t-test and comparison between stress and type of course was done with ANOVA with Tukey's HSD. Binary logistic regression analysis (using the enter method) to evaluate the influence of the independent variables on RAS and triggering factors for RAS were also dichotomized. Independent variables were entered into the regression analysis if they exhibited P < 0.5 in the bivariate analysis. The level of significance was set as P ≤ 0.05 for all comparisons.

Results

Of the 275 participants, data collected from one individual were excluded due to incomplete information. Among the study participants, 28.8% were the males and 71.2% were the females. Among the participants 19.3% were pursuing 1 st year BDS, 18.6% in 2 nd year BDS, 15.7% in 3 rd year BDS, 16.1% in 4 th year BDS, 6.9% in 2 nd year MBBS, 6.9% in 4 th year MBBS, 6.2% in medical, and 4.4% in dental were in internship [Table 1]. About 16.4% of the participants were smokers and remaining were nonsmokers.

When mean stress scores are compared, females (12.72) felt more stress compared to males (11.02), which is statistically nonsignificant [Table 2]. Final year (4 th year) MBBS students reported more stress compared to other groups followed by final (4 th year) BDS, 3 rd BDS students, and least stress was felt by 1 st year MBBS students which is statistically significant [Table 3]. Among the stress inducing factors, inability to handle personal problems and difficulty in controlling irritation in life were identified by most of the students compared to other factors [Table 4].

The overall prevalence rate of aphthous stomatitis was 78.1% and it is slightly more in males (87%) compared to females (74%) [Table 5]. Students who are pursuing final year BDS and final year MBBS courses had a high prevalence compared other courses, which is statically significant (P = 0.021) [Table 6]. Majority of the affected individuals had some triggering factors, that is, 100 out of 214 participants had more than one triggering factors, followed by exam stress, stress due to other reasons, and common cold [Table 7].

The binary logistic regression model analyzed that "having RAS experience" as the main outcome, and the following three independent variables such as gender, course pursuing and stress were included after bivariate analysis. Presence of stress increases chances of getting RAS by 3.1 times and this model was able to correctly predict 41.4% of variation with RAS (Nagelkerke r2 = 0.414), which is statistically significant [Table 8].

The etiology of RAS is multifactorial which includes various factors such as genetic, hematologic and nutritional factors as reported in the literature. [2] Among the factors much has been attributed to stress. Psychological stress triggers the immunologic activity by increasing the number of leukocytes at sites of inflammation; such pattern is commonly observed during the pathogenesis of Aphthous ulcers. [3] Pathophysiologic impact of mental stress on individuals is not uniform, especially given the complex and multiple mechanisms that affect individuals. Nevertheless, the same individual may exhibit different degrees of manifestation associated with the same kind and degree of stress. This study was conducted to assess the prevalence of aphthous stomatitis and its association with psychological stress in both medical and dental graduate students.

In this study, the overall reported 1-year period prevalence of aphthous stomatitis was quite high (78.1%), compared to studies reported by Handa et al.[16] from Jaipur, India, and Naito etal. [17] in Japanese population where prevalence is 26% and 31%, respectively. The higher period prevalence rate of RAS in the present study can be attributed to stress, which would be high in our study population compared to other populations, because medical and dental students may endure more stress due to nature of the curriculum compared to other professional courses. Among the participants, males had higher RAS prevalence (87%) compared to females (74%), which is in again contradicting to study reported by Handa etal., where females are more commonly affected than males. [16] The Mean stress scores of females were more compared to males in this study, which is similar to study reported by Singh etal. [18] in which female nursing students perceived more stress than male students. Among the participants, students who are pursuing final year course in both MBBS and BDS felt more perceived stress compared to others, which is again similar to studies, that is, higher class students felt more stress, as reported by Handa et al.[16] and Singh etal. [18] As the syllabus for final year course is more complex compared to previous years and knowledge/and performance expectations also will be high for final year students.

This study is not exceptional to few limitations. First, the cross-sectional design of this study restricts our ability to make inferences regarding the direction and strength of association between stress and RAS. However, it is less likely to imply that the domains of stress affect the 1-year period prevalence RAS than vice versa and to reduce the recall bias further exploration about duration of lesions, medications, etc., were not included in the study. Second, we used self-administered questionnaire for data collection, and the diagnosis of RAS was self-reported. However, the participants of this study were medical and dental students, who has knowledge about aphthous ulcers and we enquired the participants when they were invited to participate in survey and almost everyone confirmed their knowledge about aphthous ulcers. It is unlikely that this practice resulted in misclassifications. Finally, psychological stress increases the risk of RAS. Thus, stress preventive and management interventions may be beneficial in reducing RAS recurrence in the absence of nutritional and other known etiological factors.

Conclusions

Psychological stress found to have more impact on RAS, when compared to other factors.

Suggestions

Stress preventive and management interventions are necessary, especially both dental and medical graduate students who are pursuing final year.